Agreement Among Radiographs,Fluoroscopy and Bronchoscopy in Documentation of Airway Collapse in Dogs

Background

Airway collapse is a common finding in dogs with chronic cough, yet the diagnosis can be difficult to confirm without specialty equipment.

Hypothesis

Bronchoscopic documentation of tracheobronchial collapse will show better agreement with fluoroscopic imaging than with standard radiography.

Animals

Forty‐two dogs prospectively evaluated for chronic cough.

Methods

In this prospective study, three‐view thoracic radiographs were obtained followed by fluoroscopy during tidal respiration and fluoroscopy during induction of cough. Digital images were assessed for the presence or absence of collapse at the trachea and each lobar bronchus. Bronchoscopy was performed under general anesthesia for identification of tracheobronchial collapse at each lung segment. Agreement of imaging tests with bronchoscopy was evaluated along with sensitivity and specificity of imaging modalities as compared to bronchoscopy.

Results

Airway collapse was identified in 41/42 dogs via 1 or more testing modalities. Percent agreement between pairs of tests varied between 49 and 87% with poor–moderate agreement at most bronchial sites. Sensitivity for the detection of bronchoscopically identified collapse was highest for radiography at the trachea, left lobar bronchi, and the right middle bronchus, although specificity was relatively low. Detection of airway collapse was increased when fluoroscopy was performed after induction of cough compared to during tidal respiration.

Conclusions

Radiography and fluoroscopy are complementary imaging techniques useful in the documentation of bronchial collapse in dogs. Confirming the presence or absence of tracheal or bronchial collapse can require multiple imaging modalities as well as bronchoscopy.     

Tidal Breathing Flow‐Volume Loop Analysis for the Diagnosis and Staging of Tracheal Collapse in Dogs

Background: Tracheoscopy is generally used for the diagnosis of tracheal collapse (TC) in dogs; yet, it is costly, requires anesthesia, and can irritate the airway. The tidal breathing flow‐volume loop (TBFVL) is a safe, quick, and noninvasive pulmonary function test currently used in humans. Hypothesis: TBFVL will differentiate dogs with TC from healthy controls and contribute to disease grading. Animals: Twenty‐eight dogs with naturally occurring TC and 10 healthy controls. Methods: Cross‐sectional, prospective clinical study: The 38 dogs were assigned to one of 4 groups based on tracheoscopy results: group A (n = 10, healthy controls), group B (n = 10, grade I TC), group C (n = 10, grade II TC), and group D (n = 8, grade III TC). The TBFVL measurement was performed on all dogs and loops were assessed for their shape. Forty‐four TBFVL parameters were calculated. Results: Two types of TBFVL shapes were identified: Type I, representative of the 10 healthy controls, and Type II, representative of the 28 dogs with TC. Statistical analysis showed the dogs could be differentiated into healthy or affected by TC by 3 indices, TE/TI (expiratory time divided by inspiratory time), TI/TTOT (inspiratory time divided by total respiratory time), and EF75/IF75 (expiratory flow at end tidal volume plus 75% end tidal volume divided by inspiratory flow at end tidal volume plus 75% end tidal volume). The TC could also be graded as mild‐moderate (grades I and II) or severe (grade III), showing a diagnostic value of 97.4%. Conclusion and Clinical Importance: TBFVL is accurate, quick, noninvasive, and safe and can contribute to the diagnosis of TC in dogs.     

The Etiology and Surgical Management of Tracheal Collapse in Calves

The mean ages of 10 calves with tracheal collapse were 2.7 weeks at onset of clinical signs and 9.4 weeks at presentation for treatment. Inspiratory and expiratory dyspnea and stunted growth were the most common clinical signs. There were abnormalities of the cranial ribs consistent with healing fractures with redundant callus in eight lateral thoracic radiographs. Tracheal collapse in calves may result from cranial thoracic trauma during or soon after birth. Short polypropylene ring prostheses made from 60 ml syringe barrels were placed on the tracheas of four calves with cervical tracheal collapse. There were cranial rib masses in all calves and resection of the right first and second ribs was necessary in one calf to allow placement of prostheses. Dyspnea was relieved in all calves. One calf died of unrelated causes in year 3, and one calf had recurrence of clinical signs at month 5 and was euthanatized. In both calves, tracheal stenosis resulted from continued growth and infolding of the trachea within the constraints of the prostheses. One calf was alive at month 11, and one calf died of acute bronchopneumonia on day 2. Removal of tracheal prostheses in calves is recommended after 2 to 3 months if clinical signs recur.     

Effects of Transportation on Redox Homeostasis and Tracheal Mucus

The aim of this pilot study was to document the effects of transportation on markers of oxidative stress (OS) in blood, exhaled breath condensate (EBC), and saliva and to explore their relationships with transport-related increases in tracheal mucus. Twelve horses, six Standardbred, and six Thoroughbred, aging from 3 to 8 years, underwent an 8-hour journey during which they had no access to food or water. Clinical examinations and sampling of blood, EBC, and saliva were performed preloading, at unloading, 12 and 24 hours, and 5 days after journey. Concentration of oxidants (reactive oxygen metabolites [ROMs], advanced oxidation protein product [AOPP], ceruloplasmin [CP], hydrogen peroxide in the EBC) and antioxidants (plasma total antioxidant status [PTAS] and saliva total antioxidant status [STAS], glutathione) were determined, and the oxidative stress index (OSI = ROMs/PTAS × 100) was calculated. Respiratory endoscopy was performed at preloading and unloading, and tracheal mucus was scored. Oxidative stress variables were analyzed using proc mixed procedure with time as the fixed factor, and the variation in mucus score was analyzed by median test. The relationships between OS markers and mucus score were examined by linear regression analysis. Transportation caused a significant increase in tracheal mucus and in the concentrations of ROMs, AOPP, CP, PTAS, and STAS (all P > .05). Tracheal mucus was positively associated with ROMs and OSI (R² = 57.8, P = .004; and R² = 70.3, P < .001, respectively). However, animals did not experience OS, as reflected in the lack of changes in OSI. Overall, although the transported horses experienced oxidative and respiratory challenges, they were able to maintain redox homeostasis and did not develop clinical disease.     

Signalment,Clinical Presentation,Concurrent Diseases,and Diagnostic Findings in 28 Dogs with Dynamic Pharyngeal Collapse (2008–2013)

Background

Most information about pharyngeal collapse in dogs is anecdotal and extrapolated from human medicine. A single case report describing dynamic pharyngeal collapse in a cat has been published, but there is no literature describing this disease process in dogs.

Objective

To describe the signalment, clinical presentation, concurrent disease processes, and imaging findings of a population of client‐owned dogs with pharyngeal collapse.

Animals

Twenty‐eight client‐owned dogs with pharyngeal collapse.

Methods

Radiology reports of dogs for which fluoroscopy of the respiratory system was performed were reviewed retrospectively. Patients with a fluoroscopic diagnosis of pharyngeal collapse were included in the study population. Data regarding clinical signs, diagnostic, and pathologic findings were evaluated.

Results

Twenty‐eight dogs met the inclusion criteria. The median age of affected patients was 6.6 years, whereas median body condition score was 7/9. The most common clinical signs were coughing (n = 20) and stertor (n = 5). In 27 of 28 cases, a concurrent or previously diagnosed cardiopulmonary disorder was detected. The most common concurrent disease processes were mainstem bronchi collapse (n = 18), tracheal collapse (n = 17), and brachycephalic airway syndrome (n = 8). Fluoroscopy identified complete pharyngeal collapse in 20 of 28 dogs.

Conclusions

Pharyngeal collapse is a complex disease process that likely is secondary to long‐term negative pressure gradients and anatomic and functional abnormalities. Based on the findings of this study, pharyngeal fluoroscopy may be useful diagnostic test in patients with suspected tracheal and mainstem bronchial collapse to identify concurrent pharyngeal collapse.     

Comparison of postprandial and ceruletide serum bile acid stimulation in dogs

BACKGROUND: Postprandial (PP) serum bile acid (SBA) stimulation is an important test for detecting hepatic dysfunction in dogs. However, this test is influenced by numerous variables, and a standardized approach using an injectable cholecystokinin analog (ceruletide) may be advantageous. HYPOTHESIS: Ceruletide SBA stimulation test is more sensitive than PP SBA stimulation in dogs. ANIMALS: Animals with portosystemic shunt (PSS) (n = 11) and dogs with upper respiratory disease (URD) (n = 9) were investigated. Healthy dogs (n = 13) and dogs with other diseases (n = 17) served as controls. METHODS: All dogs underwent SBA stimulation with food and ceruletide. Stimulation blood samples were drawn at 60/120 minutes and 20/30/40 minutes, respectively. Results were compared statistically, and the sensitivity and specificity were determined with receiver-operating characteristic curves. RESULTS: Stimulated SBA were significantly higher in both study groups than in controls. For dogs with PSS, the sensitivity and specificity (>35 micromol/L) were 100% postprandially (120 minutes) and 91 and 100%, respectively, postceruletide (30 minutes). The difference between these values was not statistically significant. For dogs with URD, the sensitivity and specificity (>22 micromol/L) were 44 and 88% postprandially (120 minutes) and 100 and 88% postceruletide (30 minutes). CONCLUSIONS AND CLINICAL IMPORTANCE: Ceruletide SBA stimulation circumvents exogenous and endogenous influences associated with PP SBA stimulation. The results indicate that ceruletide SBA stimulation performs as well as PP SBA stimulation in dogs with PSS and is more sensitive for the detection of hepatic dysfunction in dogs with URD.     

The Safety and efficacy of a new self-expandable intratracheal nitinol stent for the tracheal collapse in dogs

To evaluate the potential utility of a self-expandable intratracheal nitinol stent with flared ends for the treatment of tracheal collapse in dogs, endotracheal stenting therapy was performed under fluoroscopic guidance in four dogs with severe tracheal collapse. During the 4 to 7 month follow-up, after stent implantation, clinical signs, including dyspnea and respiratory distress, dramatically improved in all dogs. The radiographs showed that the implanted stents improved the tracheal collapse, and there were no side effects such as collapse, shortening or migration of the stents. In conclusion, the self-expandable intratracheal nitinol stents provided adequate stability to the trachea and were effective for attenuating the clinical signs associated with severe tracheal collapse.     

The use of intraluminal stents for tracheal collapse in two horses: Case management and long‐term treatment

Tracheal collapse is an uncommon clinical disorder in horses but when present can be difficult to correct. Various medical and surgical procedures to correct tracheal collapse have been described in horses with variable success. Recently, the use of an intraluminal stent has been described as a treatment for tracheal collapse in a miniature horse. The long‐term management, utilising intraluminal stents, in 2 miniature horses with tracheal collapse is presented here. In particular, various complications as a result of intraluminal stent placement are described, the most persistent being the formation of granulation tissue at various regions of the stents. Multiple methods of combating granulation tissue in this situation also are discussed.